CA1044563A - Auxiliary hydrostatic wheel drive - Google Patents
Auxiliary hydrostatic wheel driveInfo
- Publication number
- CA1044563A CA1044563A CA210,976A CA210976A CA1044563A CA 1044563 A CA1044563 A CA 1044563A CA 210976 A CA210976 A CA 210976A CA 1044563 A CA1044563 A CA 1044563A
- Authority
- CA
- Canada
- Prior art keywords
- motor
- drive
- transmission control
- vehicle
- wheel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/42—Control of exclusively fluid gearing hydrostatic involving adjustment of a pump or motor with adjustable output or capacity
- F16H61/421—Motor capacity control by electro-hydraulic control means, e.g. using solenoid valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K17/00—Arrangement or mounting of transmissions in vehicles
- B60K17/04—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing
- B60K17/10—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing of fluid gearing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K17/00—Arrangement or mounting of transmissions in vehicles
- B60K17/34—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles
- B60K17/356—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles having fluid or electric motor, for driving one or more wheels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4035—Control of circuit flow
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/44—Control of exclusively fluid gearing hydrostatic with more than one pump or motor in operation
- F16H61/456—Control of the balance of torque or speed between pumps or motors
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Arrangement And Driving Of Transmission Devices (AREA)
- Control Of Fluid Gearings (AREA)
- Motor Power Transmission Devices (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
AUXILIARY HYDROSTATIC WHEEL DRIVE
Abstract of the Disclosure A supplementary hydrostatic front wheel drive for a motor grader or the like utilizes pump flow from an already existing implement system as the source of supply to operate the drive wheel motors. The drive wheel motors are of the variable displacement over center type, and the system provides equal flow to both drive wheel motors to establish a synchronized rotational speed of both drive wheel motors. The displacement of the drive wheel motors are responsive to vehicle ground speed. The drive wheel components may include friction driving means which are responsive to the primary vehicle drive system.
Abstract of the Disclosure A supplementary hydrostatic front wheel drive for a motor grader or the like utilizes pump flow from an already existing implement system as the source of supply to operate the drive wheel motors. The drive wheel motors are of the variable displacement over center type, and the system provides equal flow to both drive wheel motors to establish a synchronized rotational speed of both drive wheel motors. The displacement of the drive wheel motors are responsive to vehicle ground speed. The drive wheel components may include friction driving means which are responsive to the primary vehicle drive system.
Description
10445~3 Background of the Invention This invention relates to an auxiliary hydrostatic front wheel drive system for a vehicle and more particularly to a system which utilizes variable displacement hydrostatic drive motors.
Drive systems of the general type described herein are disclosed in U.S. Patent No. 3,458,005 to Malm et al, U.S. Patent No. 3,480,099 to Nighswonger et al, and U.S.
Patent No. 3,481,419 to Kress et al. While these systems would appear to be effective in the use for which they are designed, it is to be noted that the systems thereof utilize fixed displacement hydraulic motors for driving the front wheels of the vehicle in the auxiliary drive system thereof.
Thus, there is no teaching of a system which is specifically to be used in comblnation with fluid drive motors of the variable displacement type. Of particular interest herein is an association of the displacements of the auxiliary drive motors ln response to 8 primary drive condition of the vehicle.
It will be understood, of course, that none of the three references cited above are concerned with such a system.
Also of interest are V.S. Patent No. 3,354,978 to . - .
Budzich, disclosing a hydraulic motor responsive to a pump, U.S.
Patent No. 3,680,652 to Greene, wherein the displacement of a hydraulic motor is varied by a hand lever, and U.S. Patent No.
3,827,528 to Shaffer, wherein the displacement of a motor is responsive to motor line pressure.
Of more general interest in this area are U.S. Patent No. 2,818,699 to Clemson, U.S. Patent No. 3,153,908 to Lawrence, U.S. Patent No. 3,184,994 to Stahl, U.S. Patent No.
. . , 3,186,506 to Leach, U.S. Patent No. 3,255,840 to Tangen, U.S.
.~ Patent No. 3,272,576 to Budzich, U.S. Patent No. 3,272,279 to . ~ , .
,~
:
.
iO~S63 Budzich, U.S. Patent No. 3,302,741 to Brazuk, U.S. Patent No. 3,354,9/7 to Swift, U.S. Patent No, 3,391,753 to Anderson, U.S. Patent No. 3,361,223 to Baver, U.S. Patent No. 3,415,334 :to Vriend, U.S. Patent No. 3,469,648 to Cannon, U.S. Patent No. 3,477,547 to Kress et al, U.S. Patent No. 3,493,067 to Rumsey, U.S. Patent No. 3,522,861 to Middlesworth et al, and U.S. Patent No. 3,579,988 to Firth et al.
Summary of the Invention It i9 an obJect of this invention to provide an .10 auxlliary front wheel drive system for a vehicle which uses -variable displacement fluid motors to drive the front wheels . thereof, and wherein the displacements of such fluid motors are varied in response to a primary drive condition of the vehicle.
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It is a further ob~ect of this invention to provide :~
:~a system which, while fulfilling the above ob~ect, is simple in design and effectlve in use.
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1~4~S~3 According to the invention there is provided in a vehicle having a variable transmission control for determining a drive speed of the vehicle, an auxlllary drive system for said vehicle associated with a wheel thereof comprising a variable displacement fluid motor assoclated with : said wheel thereof, means for transmitting power from the motor to drive the wheel, a fluld pu~p, fluid circuit ~eans opera-tlvely connecting the pump and motor, and means operatlvely connectlng the transmisslon control and motor to vary the dlsplacement of the motor in response to said transmission control to provide a rotative speed of the motor correspondlng :.~ to the drive speed of the vehicle, wherein the means for trans-mitting power from the motor to drive said wheel comprise clutch means engageable upon application of fluid pressure thereto to ` effect a driving condition between the motor and wheel, and dlsengageable to disconnect the motor and wheel, and means operatively connecting the clutch means and transmission ,~
control for engaging and disengaging the clutch means in response :;
to ssid transmis~lon control.
Brief Description of the Drawings These and other objects of the inVentiOn will become ~; apparent from a study of the following specification and drawings, ~ ~ :
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1~4~S63 in which:
Fig. 1 is a schematic illustration of a first embodi-ment of auxiliary front wheel drive system for a vehicle;
Fig. 2 is a schematic illustration of a second embodiment of an auxiliary front wheel drive system for a vehicle;
Fig. 3 is a schematic illustration of a third embodi-ment of an a~iliary front wheel drive system for a vehicle;
and Fig. 4 is a schematic illustration of a fourth embodi-.:
ment of an auxiliary front wheel drive system for a vehicle.
, Description of the Preferred Embodiments Referring to Fig. 1, a variable displacement pressure ~
compensated fluid pump 10 provides pressurized fluid flow from -a fluid supply 11 associated therewith to both an implement , system and a hydrostatic front wheel drive system by conduits ~ 12,14 respectively. A priority valve 16 is disposed between .' the pump 10 and the front wheel drive system to maintain `~ adequate flow and pre~sure to the implement system (not shown).
When adequate pressure is available, the priority valve 16 shifts to allow fluid flow through the conduit 18. An ~ -on/off valve 20 is hydraulically actuated by pressurized fluid - --~ from pump 10 through a valve 22 which is controlled by a ~' solenoid. The solenoid operated valve 22 is electrically actuated and selectively responsive to operator control. With ~' valve 20 in the on position, pressurized fluid is directed to a flow divider 24 by a conduit 26. The flow divider 24 main-tains equal distribution of fluid flow to the drive motors 27 via conduits 28,30. The flow divider 24 enables the motors ~;~ 30 27 to rotate at basically the same speed. Return line 32 . accepts discharge flow from both motors 27 and directs it to .. . .
., , , .
.
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a restrictor valve 34 and further to tank 11 via a conduit 36.
The restrictor valve 34 maintains a predetermined back pressure in the system during startup which guarantees that there is an adequate amount of pressure in conduits 40, 42 which are branches of conduits 28,30 respectlvely. Pressure - is supplied from such conduits 40,42 to clutches 38 to effect a power transmitting or driving relation between the motors 27 and their respectively associated vehicle wheels 49. The connection between an output of a motor 27 and a wheel 49 may 10 be made through a planetary drive or directly, as chosen.
Upon the pressure in the system reaching a predeter-mined value, pump pressure acting against a load piston 44 in ~ the restrictor valve 34 causes the piston 44 to move against - a poppet 46 and unseat the poppet 46 fully, allowing maximum free flow to tank 11.
The motors 27 are of the variable displacement, over center type. A variable transmission control 48 determines a primary drive condition of the vehicle, and the fluid conduit means described above operatively connect the pump 10 and 20 motors 27. For example, in the preferred embodiment, a t pressure signal could be taken from any rotating component of the primary drive system of the vehicle, the rotative speed of such component being proportional to the primary drive speed of the vehicle. Such pressure would be directed to the primary drive transmission control 48 by conduit means (not shown) in a well-known manner, and conduit means interconnect the transmission control with the motors 27, to apply pressure thereto corresponding to and substantially proportional to the fluid pressure supplied to the transmission control 48, 30 determined by the primary drive condition of the vehicle.
Pressure signals directed from the primary drive transmission ,~.
' ~ "
1~4~5~3 control 48 signal the variable displacement motors 27 to shift to angles which provide rotational speeds corresponding in magnitude to that of the primary drive condition or drive speed of the vehicle. In this manner, the ground speed of the front wheels 49 approximate that of the rear driven wheels.
The front wheels 49 are of the steerable type, and the rotative speeds of the front wheels 49 and rear driven wheels of the vehicle are substantially the same. Through the use of the above-described 1OW divider, the motors 27 are driven in parallel.
Relief valve 50 protects pump 10 from excessive back pressures.
In the embodiment of Fig. 2, the operation of the system is substantially the same as that of Fig. 1. However, -in Fig. 1 clutch actuation was achieved by application of fluid ., .
pressure through branch conduits 40,42 extending from the main pressurized conduits 28,30 communicating with the motors 27.
In the Fig. 2 system, the clutch actuation is accomplished by ~ignàl pressure from the primary drive system transmission control 48 that signals the motors 27. Such clutches 38, of course, as in Fig. 1, are engageable upon application of fluid pressure thereto to effect a power transmitting or driving - condition between the respective motors 27 and wheels 49, and .. ~ .
-`s disengageable to disconnect the motors 27 and wheels 49. It will thus be seen that means operatively connect the clutches 38 and transmission control 48 for engaging and disengaging the clutches 38 in response to the transmission control 48. It ... .
will also be understood that the transmission control 48 determines a plurality of transmission control fluid pressures, in conduits 53,55,57. That is, it will be understood that the transmission control 48 may, as is well known, include a : ~ ~
. . .
, :-` ,~5 .~ c~ ~-.
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5~i3 plurality of actuating spools, and the conduits 53,55,57 may communicate with certain portions of the bores within which ; the spools are movably disposed so that the conduits are subject to appropriate transmission control fluid pressures.
Thus, upon the choosing of certain positions of such spools, pressures are directed to and through the conduits 53,55,57.
A pair of shuttle valves 59, 61 are associated wi,th these condults 53,55,57 to direct the greatest of the transmission ; control fluid pressures to the clutches 3~ for sctuation thereof.
Clutch actuation is thus responsive to transmisslon signal pressure, permitting the deletion of the restrictor valve 34 of Fig. 1 from this Fig. 2 system. That is, clutch actuation is not responsive to maintenance of a predetermined back pressure in the system. In the embodiment of Fig. 2, upon achievement of a primary drive condition, it is insured that ~ transmission signal pressure is applied through one of the ;/ appropriate conduits 53,55,57 to actuate the clutches 38.
In Fig. 3 is shown a further modification of the drlve motor portion of the system. In such Fig. 3 embodiment, clutches are not included for providing driving connection between the motors 27' and the wheels 49 associated therewith.
Rather, the drive motors 27' are of the high speed, variable displacement, over center type, such motors 27' being capable of operating at rotational speeds of up to 10,000 R.P.M. The motor control method is similar to that used in Fig. 1, that is, transmission control pressure-from the prlmary drive system 4~ -~
~ signals the motors 27' to shift their displacement to an angle - which establishes the rotational speed of the drive wheel motors 27' approximately equal in magnitude to that in the primary -1 30 drive wheel system.
In Fig. 4 is shown a system that is a modification .
.~
, - . .
- -1~)445~3 of the system shown in Pig. 3, in that the motor control has been changed to provide a pilot control for the motors 27' which is actuated by an external signal. Pressurized fluid is directed to the drive wheel motors 27' by conduits 28,30, and the return flow is directed to tank via conduit 32. A
pair of motor control valves 52 direct pressurized fluid in conduits 54,56, branches of conduits 28,30 respectively, to the motors 27'. The motor control valves 52 receive a pilot slgnal which corresponds to the vehicle speed and cause8 the control valves 52 to shift and direct reduced pressure to the motor~ 27', which, in turn, causes the motors 27' to shift to a displacement which corresponds to the rotational speed of the drive wheels. The control valves 52 are of the modulating type and direct reduced pressure to provide variable displace- `
`~ ment control. Conduits 58,60 are connected to conduit 32, which is ultimately connected to tank. The pilot signal lines 62 which actuate the control valves 52 could so actuate such control valves 52 electrically, hydrau}ically or pneumatically.
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Drive systems of the general type described herein are disclosed in U.S. Patent No. 3,458,005 to Malm et al, U.S. Patent No. 3,480,099 to Nighswonger et al, and U.S.
Patent No. 3,481,419 to Kress et al. While these systems would appear to be effective in the use for which they are designed, it is to be noted that the systems thereof utilize fixed displacement hydraulic motors for driving the front wheels of the vehicle in the auxiliary drive system thereof.
Thus, there is no teaching of a system which is specifically to be used in comblnation with fluid drive motors of the variable displacement type. Of particular interest herein is an association of the displacements of the auxiliary drive motors ln response to 8 primary drive condition of the vehicle.
It will be understood, of course, that none of the three references cited above are concerned with such a system.
Also of interest are V.S. Patent No. 3,354,978 to . - .
Budzich, disclosing a hydraulic motor responsive to a pump, U.S.
Patent No. 3,680,652 to Greene, wherein the displacement of a hydraulic motor is varied by a hand lever, and U.S. Patent No.
3,827,528 to Shaffer, wherein the displacement of a motor is responsive to motor line pressure.
Of more general interest in this area are U.S. Patent No. 2,818,699 to Clemson, U.S. Patent No. 3,153,908 to Lawrence, U.S. Patent No. 3,184,994 to Stahl, U.S. Patent No.
. . , 3,186,506 to Leach, U.S. Patent No. 3,255,840 to Tangen, U.S.
.~ Patent No. 3,272,576 to Budzich, U.S. Patent No. 3,272,279 to . ~ , .
,~
:
.
iO~S63 Budzich, U.S. Patent No. 3,302,741 to Brazuk, U.S. Patent No. 3,354,9/7 to Swift, U.S. Patent No, 3,391,753 to Anderson, U.S. Patent No. 3,361,223 to Baver, U.S. Patent No. 3,415,334 :to Vriend, U.S. Patent No. 3,469,648 to Cannon, U.S. Patent No. 3,477,547 to Kress et al, U.S. Patent No. 3,493,067 to Rumsey, U.S. Patent No. 3,522,861 to Middlesworth et al, and U.S. Patent No. 3,579,988 to Firth et al.
Summary of the Invention It i9 an obJect of this invention to provide an .10 auxlliary front wheel drive system for a vehicle which uses -variable displacement fluid motors to drive the front wheels . thereof, and wherein the displacements of such fluid motors are varied in response to a primary drive condition of the vehicle.
:,~
It is a further ob~ect of this invention to provide :~
:~a system which, while fulfilling the above ob~ect, is simple in design and effectlve in use.
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. ~ , .
.", :i' ~ '-:
' :
.`' ;)``
., .
,'`' g~
. .
..~
:., .,: . . ~ .
1~4~S~3 According to the invention there is provided in a vehicle having a variable transmission control for determining a drive speed of the vehicle, an auxlllary drive system for said vehicle associated with a wheel thereof comprising a variable displacement fluid motor assoclated with : said wheel thereof, means for transmitting power from the motor to drive the wheel, a fluld pu~p, fluid circuit ~eans opera-tlvely connecting the pump and motor, and means operatlvely connectlng the transmisslon control and motor to vary the dlsplacement of the motor in response to said transmission control to provide a rotative speed of the motor correspondlng :.~ to the drive speed of the vehicle, wherein the means for trans-mitting power from the motor to drive said wheel comprise clutch means engageable upon application of fluid pressure thereto to ` effect a driving condition between the motor and wheel, and dlsengageable to disconnect the motor and wheel, and means operatively connecting the clutch means and transmission ,~
control for engaging and disengaging the clutch means in response :;
to ssid transmis~lon control.
Brief Description of the Drawings These and other objects of the inVentiOn will become ~; apparent from a study of the following specification and drawings, ~ ~ :
.'` .
.:~
'`~ , ,~:, .
~ C
:, , ' ':'' "
1~4~S63 in which:
Fig. 1 is a schematic illustration of a first embodi-ment of auxiliary front wheel drive system for a vehicle;
Fig. 2 is a schematic illustration of a second embodiment of an auxiliary front wheel drive system for a vehicle;
Fig. 3 is a schematic illustration of a third embodi-ment of an a~iliary front wheel drive system for a vehicle;
and Fig. 4 is a schematic illustration of a fourth embodi-.:
ment of an auxiliary front wheel drive system for a vehicle.
, Description of the Preferred Embodiments Referring to Fig. 1, a variable displacement pressure ~
compensated fluid pump 10 provides pressurized fluid flow from -a fluid supply 11 associated therewith to both an implement , system and a hydrostatic front wheel drive system by conduits ~ 12,14 respectively. A priority valve 16 is disposed between .' the pump 10 and the front wheel drive system to maintain `~ adequate flow and pre~sure to the implement system (not shown).
When adequate pressure is available, the priority valve 16 shifts to allow fluid flow through the conduit 18. An ~ -on/off valve 20 is hydraulically actuated by pressurized fluid - --~ from pump 10 through a valve 22 which is controlled by a ~' solenoid. The solenoid operated valve 22 is electrically actuated and selectively responsive to operator control. With ~' valve 20 in the on position, pressurized fluid is directed to a flow divider 24 by a conduit 26. The flow divider 24 main-tains equal distribution of fluid flow to the drive motors 27 via conduits 28,30. The flow divider 24 enables the motors ~;~ 30 27 to rotate at basically the same speed. Return line 32 . accepts discharge flow from both motors 27 and directs it to .. . .
., , , .
.
:: ~
., , -. . - . , - - . - -, - -:
. ::- : :. , :-, . , :
~-- ~Q~56;~
a restrictor valve 34 and further to tank 11 via a conduit 36.
The restrictor valve 34 maintains a predetermined back pressure in the system during startup which guarantees that there is an adequate amount of pressure in conduits 40, 42 which are branches of conduits 28,30 respectlvely. Pressure - is supplied from such conduits 40,42 to clutches 38 to effect a power transmitting or driving relation between the motors 27 and their respectively associated vehicle wheels 49. The connection between an output of a motor 27 and a wheel 49 may 10 be made through a planetary drive or directly, as chosen.
Upon the pressure in the system reaching a predeter-mined value, pump pressure acting against a load piston 44 in ~ the restrictor valve 34 causes the piston 44 to move against - a poppet 46 and unseat the poppet 46 fully, allowing maximum free flow to tank 11.
The motors 27 are of the variable displacement, over center type. A variable transmission control 48 determines a primary drive condition of the vehicle, and the fluid conduit means described above operatively connect the pump 10 and 20 motors 27. For example, in the preferred embodiment, a t pressure signal could be taken from any rotating component of the primary drive system of the vehicle, the rotative speed of such component being proportional to the primary drive speed of the vehicle. Such pressure would be directed to the primary drive transmission control 48 by conduit means (not shown) in a well-known manner, and conduit means interconnect the transmission control with the motors 27, to apply pressure thereto corresponding to and substantially proportional to the fluid pressure supplied to the transmission control 48, 30 determined by the primary drive condition of the vehicle.
Pressure signals directed from the primary drive transmission ,~.
' ~ "
1~4~5~3 control 48 signal the variable displacement motors 27 to shift to angles which provide rotational speeds corresponding in magnitude to that of the primary drive condition or drive speed of the vehicle. In this manner, the ground speed of the front wheels 49 approximate that of the rear driven wheels.
The front wheels 49 are of the steerable type, and the rotative speeds of the front wheels 49 and rear driven wheels of the vehicle are substantially the same. Through the use of the above-described 1OW divider, the motors 27 are driven in parallel.
Relief valve 50 protects pump 10 from excessive back pressures.
In the embodiment of Fig. 2, the operation of the system is substantially the same as that of Fig. 1. However, -in Fig. 1 clutch actuation was achieved by application of fluid ., .
pressure through branch conduits 40,42 extending from the main pressurized conduits 28,30 communicating with the motors 27.
In the Fig. 2 system, the clutch actuation is accomplished by ~ignàl pressure from the primary drive system transmission control 48 that signals the motors 27. Such clutches 38, of course, as in Fig. 1, are engageable upon application of fluid pressure thereto to effect a power transmitting or driving - condition between the respective motors 27 and wheels 49, and .. ~ .
-`s disengageable to disconnect the motors 27 and wheels 49. It will thus be seen that means operatively connect the clutches 38 and transmission control 48 for engaging and disengaging the clutches 38 in response to the transmission control 48. It ... .
will also be understood that the transmission control 48 determines a plurality of transmission control fluid pressures, in conduits 53,55,57. That is, it will be understood that the transmission control 48 may, as is well known, include a : ~ ~
. . .
, :-` ,~5 .~ c~ ~-.
:- -: . . , - .
:: : . -. : . ::
5~i3 plurality of actuating spools, and the conduits 53,55,57 may communicate with certain portions of the bores within which ; the spools are movably disposed so that the conduits are subject to appropriate transmission control fluid pressures.
Thus, upon the choosing of certain positions of such spools, pressures are directed to and through the conduits 53,55,57.
A pair of shuttle valves 59, 61 are associated wi,th these condults 53,55,57 to direct the greatest of the transmission ; control fluid pressures to the clutches 3~ for sctuation thereof.
Clutch actuation is thus responsive to transmisslon signal pressure, permitting the deletion of the restrictor valve 34 of Fig. 1 from this Fig. 2 system. That is, clutch actuation is not responsive to maintenance of a predetermined back pressure in the system. In the embodiment of Fig. 2, upon achievement of a primary drive condition, it is insured that ~ transmission signal pressure is applied through one of the ;/ appropriate conduits 53,55,57 to actuate the clutches 38.
In Fig. 3 is shown a further modification of the drlve motor portion of the system. In such Fig. 3 embodiment, clutches are not included for providing driving connection between the motors 27' and the wheels 49 associated therewith.
Rather, the drive motors 27' are of the high speed, variable displacement, over center type, such motors 27' being capable of operating at rotational speeds of up to 10,000 R.P.M. The motor control method is similar to that used in Fig. 1, that is, transmission control pressure-from the prlmary drive system 4~ -~
~ signals the motors 27' to shift their displacement to an angle - which establishes the rotational speed of the drive wheel motors 27' approximately equal in magnitude to that in the primary -1 30 drive wheel system.
In Fig. 4 is shown a system that is a modification .
.~
, - . .
- -1~)445~3 of the system shown in Pig. 3, in that the motor control has been changed to provide a pilot control for the motors 27' which is actuated by an external signal. Pressurized fluid is directed to the drive wheel motors 27' by conduits 28,30, and the return flow is directed to tank via conduit 32. A
pair of motor control valves 52 direct pressurized fluid in conduits 54,56, branches of conduits 28,30 respectively, to the motors 27'. The motor control valves 52 receive a pilot slgnal which corresponds to the vehicle speed and cause8 the control valves 52 to shift and direct reduced pressure to the motor~ 27', which, in turn, causes the motors 27' to shift to a displacement which corresponds to the rotational speed of the drive wheels. The control valves 52 are of the modulating type and direct reduced pressure to provide variable displace- `
`~ ment control. Conduits 58,60 are connected to conduit 32, which is ultimately connected to tank. The pilot signal lines 62 which actuate the control valves 52 could so actuate such control valves 52 electrically, hydrau}ically or pneumatically.
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Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a vehicle having a variable transmission control for determining a drive speed of the vehicle, an auxiliary drive system for said vehicle associated with a wheel thereof comprising a variable displacement fluid motor associated with said wheel thereof, means for transmitting power from the motor to drive the wheel, a fluid pump, fluid circuit means opera-tively connecting the pump and motor, and means operatively connecting the transmission control and motor to vary the displacement of the motor in response to said transmission control to provide a rotative speed of the motor corresponding to the drive speed of the vehicle, wherein the means for trans-mitting power from the motor to drive said wheel comprise clutch means engageable upon application of fluid pressure thereto to effect a driving condition between the motor and wheel, and disengageable to disconnect the motor and wheel, and means operatively connecting the clutch means and transmission control for engaging and disengaging the clutch means in response to said transmission control.
2. The apparatus of claim 1 wherein the transmission control determines a plurality of transmission control fluid pressures, and further comprising means for applying the greatest of the transmission control fluid pressures to the clutch means.
3. The apparatus of claim 2 wherein the means for applying the greatest of the transmission control fluid pressures to the clutch means comprise shuttle valve means.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US43296874A | 1974-01-14 | 1974-01-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1044563A true CA1044563A (en) | 1978-12-19 |
Family
ID=23718303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA210,976A Expired CA1044563A (en) | 1974-01-14 | 1974-10-08 | Auxiliary hydrostatic wheel drive |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4071106A (en) |
| JP (1) | JPS50102022A (en) |
| CA (1) | CA1044563A (en) |
| ZA (1) | ZA747134B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5226338A (en) * | 1975-08-25 | 1977-02-26 | Nippon Kokan Kk | Method and device of tension control for continous annealing plant |
| US4177870A (en) * | 1978-05-30 | 1979-12-11 | Deere & Company | Hydrostatic front wheel drive system |
| JPS5895323U (en) * | 1981-12-23 | 1983-06-28 | 株式会社小松製作所 | Straight line compensation control device for hydraulically driven vehicles |
| US7004870B2 (en) * | 2004-02-25 | 2006-02-28 | Dana Corporation | Integrated torque and roll control system |
| US8635867B2 (en) * | 2004-07-15 | 2014-01-28 | Parker-Hannifin Corporation | Hydrostatic transmission |
| US20070137918A1 (en) * | 2005-11-23 | 2007-06-21 | Xingen Dong | Mounting of hydrostatic transmission for riding lawn mower |
| US20080120974A1 (en) * | 2006-11-24 | 2008-05-29 | Parker-Hannifin Corporation | Integrated hydrostatic transmission for left and right wheel drive |
| US7823897B2 (en) * | 2006-10-04 | 2010-11-02 | Deere & Company | Vehicular drive system with FWD-only mode and associated method |
| US8061466B2 (en) * | 2008-07-24 | 2011-11-22 | Caterpillar Inc. | Wheel tractor scraper rear wheel drive assist and method of operation |
| US8051916B2 (en) * | 2008-07-24 | 2011-11-08 | Caterpillar Inc. | Rear wheel drive assist for a wheel tractor scraper |
| US8857171B2 (en) * | 2010-02-11 | 2014-10-14 | Parker-Hannifin Corporation | Integrated hydrostatic transmission |
| JP6815442B2 (en) * | 2019-06-26 | 2021-01-20 | 日本国土開発株式会社 | Scraper vehicle and its control method and towing vehicle |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3272279A (en) * | 1964-06-08 | 1966-09-13 | Budzich Tadeusz | Fluid pressure operated drive and clutch systems |
| US3354978A (en) * | 1965-07-12 | 1967-11-28 | Budzich Tadeusz | Speed responsive hydrostatic device |
| US3458005A (en) * | 1967-11-28 | 1969-07-29 | Deere & Co | Hydrostatic front wheel drive for a tractor |
| US3480099A (en) * | 1967-11-28 | 1969-11-25 | Deere & Co | Interlocked change speed and auxiliary hydrostatic front wheel drive motor controls |
| US3481419A (en) * | 1967-11-28 | 1969-12-02 | Deere & Co | Auxiliary hydrostatic front wheel drive system with drive motors connected for parallel or series operation |
| US3506081A (en) * | 1967-12-29 | 1970-04-14 | Houdaille Industries Inc | Wheel driving hydraulic motor circuits |
| US3535984A (en) * | 1968-03-28 | 1970-10-27 | Trans Wheel Inc | Axial piston pump-motor system |
| US3680652A (en) * | 1971-01-14 | 1972-08-01 | Clarence Kirk Greene | Hydraulic drive for multi-axle vehicles |
| US3827528A (en) * | 1972-10-10 | 1974-08-06 | Towmotor Corp | Low cost auxiliary hydrostatic drive for trucks |
| US3882980A (en) * | 1973-04-27 | 1975-05-13 | Caterpillar Tractor Co | Transmission control system with dual purpose modulating |
-
1974
- 1974-10-08 CA CA210,976A patent/CA1044563A/en not_active Expired
- 1974-11-06 ZA ZA00747134A patent/ZA747134B/en unknown
-
1975
- 1975-01-10 JP JP50005049A patent/JPS50102022A/ja active Pending
-
1976
- 1976-09-27 US US05/727,187 patent/US4071106A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US4071106A (en) | 1978-01-31 |
| ZA747134B (en) | 1975-11-26 |
| JPS50102022A (en) | 1975-08-13 |
| AU7434674A (en) | 1976-04-29 |
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